Good, that gives you the entire gamut of options. If you do change your team, you'll need to update that. My Tyranitar is extremely fast, with a 31 IV and max EVs in Speed; that means, despite a bad 71 to start off with as Mega Tyranitar, it can now outspeed anything with a base Speed of 115 or lower, even those with a positive nature enhancing the Speed. And Greninja is lightning quick except when taken out with priority moves; Speed is its best stat, and it also has the 31/252 set on it, so you will likely not be able to outspeed it for the Surf (Rhyperior) and Ice Punch (Salamence), among other things. You'll have to get crafty to get them out. But that's what the challenge is, to figure out how to deal with a good team of well-crafted Pokémon.
Keep in mind, with the same team, you can actually build multiples of the same species and swap them in and out; only the species have to stay the same. So you don't have to wipe out all your work on your current six; feel free to build others and interchange them. :)